Express your answer as a mixed number simplified to lowest terms. $11\dfrac{2}{3}-9\dfrac{2}{7} = {?}$
Answer: Separate the whole numbers from the fractional parts: $= {11} + {\dfrac{2}{3}} - {9} - {\dfrac{2}{7}}$ Bring the whole numbers together and the fractions together: $= {11} - {9} + {\dfrac{2}{3}} - {\dfrac{2}{7}}$ Subtract the whole numbers: $=2 + {\dfrac{2}{3}} - {\dfrac{2}{7}}$ Find a common denominator for the fractions: $= 2+\dfrac{14}{21}-\dfrac{6}{21}$ Subtract the fractions: $= 2+\dfrac{8}{21}$ Combine the whole and fractional parts into a mixed number: $= 2\dfrac{8}{21}$